Resonant combustion device for heating engines and similar structures



I. E. KAMM ETAL RESONANT COMBUSTION DEVICE FOR HEATING May 22, 1956 ENGINES AND SIMILAR STRUCTURES Filed Nov. 17, 1950 III \IIII'HIIIIIIIIIIIIIIIIHUIIIIHIITIH L III I 1-- Mm/XW 4 RESONANT COMBUSTION DEVICE FOR HEATING ENGINES AND SIMILAR STRUCTURES The present invention relates to heaters and, more particularly, to heaters for heating automobile and engines, as Well as the cooling systems which'rn tay be associated with such engines. .1 1. q I

Devices ot this type 'as heretofore s ggestesi fior such purpose make use .Qf fl'lfl well-known principle Qf lBGGMS'tK-Y resonance or, more-specifically, of combustion with detonation of :fuel-nirrnirtnres at atmospheric pressure :in periodic cycles. Following this principle, ages jet leaves a relatively long tube or pipe are high average speed and is produced in conformity with the natural resonance period of the tube or pipe by :the increase in temperature and pressure resulting from the combustion.

:However, the heretoiore *knowtn devices of the above- :mentioned type, working according to the acoustic mesons anceprinciple, have. the drawbacks .tthat they are, ,too' complicated and expensive, too difficult to start and, after a United States Patent Wunibald I. E. Kamm, Willy Krautter, and Kurt Staiger,

having been started, have the tendency to tail or stop" again v\prior to the establishment of sufiici'ently stab e :con- 'ditions with regard to the natural ;nesonanee;iperiod (of f-the stube tor pipe and the pressure -oscillations'of the :fuelmixture.

It is, therefore, an kobjeot, of the present-invention no provide for an improveflnnanner oftlheatingiintornal cornbustion'engines and like-thy overcoming short;-

-comings tpreviously girilrierent in the 'stituoture :and opena I ration :of convernional, acoustically resonant heaters.

Another object :is (to'provide tin an (extremely cconomi cal, practical :m'anner fiorlc'entain starting and unfailing operation :by cyclic pulsations (of an :acoustically'rresonant heater.

.a heating device of the gabove rnentioned nnpe' which @9831 easily rbe'handled and manually be actuated so as stoinsure a proper stablezand ".fianltless rtnansition tfrom" ithe starting flame to the operating rfiame. 1

.A "further tobjecttofrthis rinvention consists injthe gpnovision of a heater tor heating :antomobileiand rather -engines andfior cooling systems therefor, :zin ywhich the combustion will start at unifor-m pressure and may the changed gradually into combustion with detonation with the change -from combustion a't uniform pressure into 1145 :It is still another object of this JiIIVEHtlOIl toprovide 1 illustrates a longitudinal section through the embodiments of aheater according to the present invention. 1 5 t Fig. 2 is a bottom view of the heating device of Fig. 1 and shows supporting means for selectively mounting the heating device in a substantially vertical and inclined position. l

Fig. 3 represents a cross section through the lower part of the heater and illustrates the nozzle and control mechanism therefor.

General arrangement trance or mouth of the combustion chamhergwhile me ns are associated with the t bular control member for adiusting the same relative o he fiuel admission valve and the mouth of the combustion chamber. The tubular control member is substantially ,coaxial with both the outlet of 5511615 1 admission valve and the m uth of the combustion chamber. this way, th space betwe n the valve outlet and the adjacent end of the tubular control member and also he space between the Opposite end of .the cont-rel member and the mou h of the combustion chambenumay be adjus ed to allow m r or less air to enter therebetween tor admixture with the fuel as. it t w v According to a further feature of this invention, the needle or control element {9f the fuel admission valve is adjusted automatically within a predetermined range in conformity with the :-fuel gas pressure which, in its turn, changes in conformity with the temperature developed (in :the combustion chamber. More specifically, the .Sfue'l control element is qunder the influence of at least :two tdifierently strong springs which normally hold the control element {in its closed position. These springs cooperate with .difierentstop means in such .a manner that the control element in response to. a predetermined gas pressure opens first against the thrust of the weaker spring :by a predetermined distance, and thereafter, in response-to an increased gas pressure, opens againstzthe thrust of the stronger spring tby, :a distance greater than he said lfif-St mentioned predetermined distance. TglleSe different strokes ,of the control element correspond to the two: differentoperating conditions, namely, below and within the :natural resonance :period of the blowing tube or pipe.

According to a preferred {embodiment of the present invention, the'conttol element 1185 Additionally .;ass0 cjiatedtherewithtmaullallywperableqmeans'tto allow adjust- ;combustion with detonation or per'iodically changing pressure will be effected "automatically.

A' stil .further object of this invention consists "in the provision-of a heaterfforiheating up engines and/or coo1- 'ing systems therefor, in which the. operating flame will .autornaticallybe controlled withinithe range of "the natural resonance period of thetu'be from which the heat gases ,are blown while said flame will bring about the .Qpressure required .ior the blowing action! These and other ohjectsand advantages or the .inven- ,tion will appear ere clearly iron; following spedfl ever desired.

ment and actuation of'tthe control element by hand, when- .Structunal arrangement Designation herein of structural members, such as lid and bottom, .and the use of expressions such as idownwardlyf refer to the heating device .as viewed .in [its substantially upright position when its ,operatiqn ,is started.

,Referring now to the drawing in detail, the s tr u cture shown therein substantially comprises a. casing g'e nerally vdesignated '1 which consistsprim'arilyof .a bottom por- 'tion 2 .anda cylindrical portion 3 connected to the bot tom portion 2 in any desired manner, for instance, by.

welding. The bottom portion 2 of the casing 1 carries the fuel admission valve, generally designated 4, which comprises primarily a cup-shaped housing 5 closed by the bottom piece 6, which may be connected to the housing in any convenient manner. The housing 5 is provided with a slot 7 for a purpose to be explained later. Connected to the bottom piece 6 by means of bolts 8 and nuts 9 is a spring member 10, which acts as a ratchet and cooperates with a grooved disc 11. The disc 11 is mounted on a square-shaped portion 12a of a bolt 12 and is held against a flange 12b of the bolt 12 by a nut 13. The bolt 12 is provided with a second threaded portion 14 threadedly engaging the stud 15 forming a part of the bottom piece 6. The bolt 12 ends in a guiding pin 16 which engages with play, for a purpose which will be clear later, a bore 17a of a bolt 17. The bolt 17 containing the bore 17a passes through a lever 18 having a cranked portion 18a which surrounds the adjacent bored portion with play. The lever 18 is supported on the bolt 17 by' a snap spring 19, a washer 20 and the bolt head 17b integral with the bolt 17. r

The inneimost end of the lever 18 is engaged by one end of a coil spring 21, the other end of which rests on a spring cup 22 which is supported with play by the adjacent bolt 8. Similarly, that end of the lever 18 which is inside the housing 5 and adjacent the slot 7 is engaged by one end of a coil spring 23, the other end of which rests upon a spring cup 24. However, according to the present arrangement, the coil spring 23 is weaker than the coil spring 21. It will furthermore be noticed that the spring cup 24 surrounding with play the adjacent bolt 8 and supported thereby is closer to the lever 18 than the spring cup 22. Thus, when the lever 18 is moved downwardly, first the spring 23 will yield until the lever portion adjacent the outwardly extending end of the lever is arrested by abutting the spring cup 24, whereupon further pressure acting on the cranked portion of the lever 18 will cause the stronger spring 21 to yield up to a maximum stroke determined bythe engagement of the adjacent lever portionwith the spring cup 22. It will be appreciated that the bolts 8 may be adjusted to vary the compression of the springs 21 and 23 and the maximum strokes of adjacent lever portions.

The bolt 17 threadedly engages the valve needle 25 which extends through the nozzle 26. The needle 25 is provided with flattened portions 25a (preferably three of such portions evenly distributed around the periphery of supply pipe 22, while the smaller end of the bore 28 communicates with an annular chamber 38. Mounted within the annular chamber 30 is a bellows 31, one end of of which is clamped between. the blunt end of the valve needle 25 and the adjacent flanged portion of the bolt a threaded ring 32 threadedly engaging the threaded portion 33 of the housing 5 of the fuel admission valve 4 and the adjacent end of the valve head 27, likewise threadedv17. The other end of the bellows 31 is clamped between ly engaging the threaded portion 33. Thus, the bellows 31 is subject to the gas pressure prevailing in the cham ber 30 and is adapted in response to this pressure to expand so that it will move the valve needle 25 rightwardly with regard to the drawing, thus increasing the free passage for the gas through the nozzle 26. It will also be appreciated that when the needle thus moves rightwardly it will act on the cranked portion of the lever 18 and actuate the same.

The entire valve assembly 4 is supported by the bottom portion 2 and clamped thereto by the valve head 27 and the housing 5. Mounted beneath the collar 34 of the valve head 27 and the adjacent part of the bottom por- 4 f tion 2 is a wick 35 (see Fig. 1), which may be of any convenient material as, for instance, asbestos. The wick is held in place by means of a spring disk 36.

Mounted in substantially axial arrangement with the needle 25 is a control tube 37. This tube is supported by a guide mechanism, generally designated 38. This guide mechanism comprises two parallel arms or levers 39 and 40 pivotally connected to the casing 1 at 41 and 42 respectively. The lever 39 is pivoted to the control tube 37 at 43 and, similarly, the lever 40 is pivotally connected to the control tube 37 by a pivot 44. The lever 39 is furthermore connected through a lever 45 with a manually operable lever 46 provided with a handle 47. The lever 46 is provided with a ratchet 48 cooperating with a grooved segment 49 connected to the casing in any. convenient manner. The lever 46 is movable around a fixed pivot 50. Thus it will be clear that shifting of the lever 46 around the pivot 50 in one or the other direction will move the control tube 37 towards or away from the nozzle 26.

I Adjacent to but spaced from that end of the control tube 37 which is remote from the nozzle 26 is a main combustion space defined by a combustion chamber 51. As will be clear from the drawing, the combustion chamber 51 expands away from its mouth 52 and merges into a cylinder portion 51a which is followed by a tapered portion 51b. Connected to the tapered portion 51b is the resonance pipe 53, which latter ends in the slightly flared portion 54.

That part of the cylindrical portion 3 of the casing 1 which surrounds the combustion chamber 51 between the mouth thereof and the adjacent end of the cylindrical portion 51a is constructed as a fuel container and, therefore, is provided with a lid 56 and bottom 57 which are conveniently fastened in fluid-tight relation to the casing land the combustion chamber 51. The lid 56 is provided with a normally plugged inlet opening 58 for admitting fuel into the fuel container 55. This filling action is preferably efiected when the heater is in its up ward position. In order to be able to mount the heater in vertical or inclined position, the heater is provided with legs 59, 60 which frictionally engage trunnion element 62 provided on opposite sides, Fig. 2, of the easing 1, Fig. 1, by band structure 62a closely encircling the casing. If desired, anypositive locking'means may be associated with the legs 59 so as to prevent any accidetal turn over or collapse of the support formed by the latter.

As will also be seen from the drawing, the fuel supply pipe 29 has a large portion located in the fuel tank 55, which portion passes around and in close proximity to the combustion chamber and ends adjacent the inlet opening 58. Furthermore, the resonance pipe 53 is surrounded in spaced relationship thereto by an outer pipe 63 which extends along and coaxial with the resonance pipe 53, Preferably the pipe 63 may be elongated by a second outer pipe, 64 telescope-like connected to the pipe 64. The inner position of the outer pipe 64 is reached when the inner end of-this pipe abuts the funnel-shaped portion 65 of air inlet chamber 66 connected to the cylindrical portion 3 of the casingl. The air inlet opening of this chamber is designated by the reference numeral 67. The outer position of the pipe 64 is fixed by engagement of the inwardly turned end 64a with the outwardly turned end 63a of the pipe 63. The outer tubes 63, 64 and chamber 65 servea twofold purpose, namely, to reduce the delivery temperature of the heating gas applied to the motor or cooling system therefor to be heated, and also to absorb heat from the resonance pipe so as to cool the same to a desired extent. Finally, the casing 1 adjacent the bottom portion 2 thereof is provided with a window 68, normally closed, but adapted to be opened to allow the introduction of a match to ignite the wick 35 for starting purposes, while other additional openings 70, which may also selectively be more or less closed, are

provided in the casingiadjacent thebottom portion therev of for admitting air towards the nozzle-opening. Forieasy handling of the apparatus the device has connected there- -to-the handle 69.

Operation In order to start the device, the device is preferably placed 'in more 'or 'less vertical position and the disk or hand wheel 11 is turned so as to move the "bolt 14 away from the bolt 17 to such an'extent that the lever 18 when actuated can abut the spring cups 23 and "22. The disk 11 will be held in its desired position against accidental movement by flie spring member 10. Furthermore, 'the wick 35 is saturated with fuel such as gasoline. This may be effected by pressing the outwardly extending arm of the lever 18 downwardly, thuspullingthe needle '25 downwardly and allowing 'fuel to overflow the nozzle into the wick. Thereupon the window *68 is opened and, for in- ;stance, a match is introduced to ignite the fuel on the Wick.

After the flame has thus been started, the handle 47 is m adjusted so as to bring the control tube '37 relativelyclose "to the nozzle26. The control tube "is secured in its 'adjusted position by the engagementlof the ratchet withthe "respective grooved segment 49. The :thus started flame draws air into the control tube 37 and in the latter forms the combustible fuel-air mixture, which is ignited by the starting flame. As long as the coupling between the control tube 37 and the combustion chamber 51 is loose, i. e., the-distance between these elements is relatively great,

a combustion flame will develop -in the control tube '37 which burns evenly, i. e.,-at evenpressure. The thus produced flame heats up the combustion chamber and, therefore, also the fuel pipeline 29 surrounding the same. As soon as the wall temperature of the control tube 37 and the combustion chamber 51 rises and as soon as the gas jetleaving the nozzle increases, the combustion at I even pressure changes into acombustion'withdetonations.

These detonations first occur at low frequency and atlow increase in pressure, during which time the combustion vtakes place 'in the tube 37 and combustion chamber 51.

Gradually the center of the combustion .zone moves from tube 37 into the main combustion space in the combustion -;chamber :51. Now, the control tube 37 is adjusted by nneans of the handle 47 :so :as to establish a closer coupling with the combustion chamber 51, thus modifying "the acoustical resonance .of the overall combustion space,

including that within the :tube '37 together with the =main combustion space in the chamber 51. As a result thereof, the combustion with detonation merges into a combustion with detonation corresponding to the acoustic natural resonance period of the entire resonance system composed'of the control tube 37, combustion chamber "51 and resonance .pipe '53. The device has now reached its proper operative condition and works in acoustic reso- =nance,, with combustion the combustion chamber at the frequency determined by the'entire system. and at a pressure inherent to" operation at resonance. When-the ideviceis in operation, the telescopic pipe 64 may be pulled outwardly and air will be drawn in through the opening- 67, pass around and cool the resonance pipe 53 and at 'the outer end will mix withthe gases passing'through the resonance pipe. The device may then by grasped by-the handle 69 and either manually applied'toward the motor or cooling system to be heated, or may beplaced on its -legsS9, 60 with the desired incjlination so as to cause the escaping gases to heatfup the engine or cooling-system :there'for. 1

In connection with the transition from combustion at even pressure into combustion with detonation, it maybe nnentioned that this transition, in addition to 'thecoup'ling :between tube 37 and the mouth 52 0f the combustion chamber, is also influenced by the temperature condition of the "device. At low temperature the transition occurs when thedistance between the tube 37 :and the mouth '52 is rather small, whereas at hig'her temperature the transition will be effected already .at a larger distance between the tube37 and-the mouth-52. V a

With the increasing temperature of :the combustion chamber and thereby also of',thefuel pipe'29, the gas pressure in the fuel pipe and, therefore, in the ehaniber 3Z0 willincrease- This increase in pressure causes .an extension of the bellows 3 1 with the resu'ltthat'the needle valve f25will-be moved downwardly so that alarger gas 'jetfwill -leave the nozile 26. The arrangement is such that during thiseXpan-sion of the bellowsthelever 18 will movedownwardly together with the valve needle '25 and will first causeacompress'ion of the weaker spring'23 until the adjacent portion of the lever'a'buts the spring cup '24. 'Dur; ing this movement the lever has pivoted about its innermost end. When the gas pressure "in chamber 30 increases further, the bellows will also expand further and the lever 18 will compressthe stronger spring '21 until the adjacent lever portion abutsthe spring cup 22. During this operationthe lever -18'is pivoting about an abutment point with the spring clip '24. It will thus be seen thatduring the operation of the device the gas supply governs itself automatically in conformity with the gas pressure developed in the system. When the device has =completedits -heating -up operation, the band wheel or disc ll'isl again rotated, but in this "instance, so as 'to cause the bolt 12 to engage and move the bolt 17 leftwardly with regard to the drawing, until the needle '25 tightly closes the'nozzle opening. The device may now be safely stored away.

It is, of course, understood that the present invention "is by no means "limited to the particular construction'shown in the drawings, but also comprises any modifications within-the seope of'the appended claims.

What We claim is:

l. A 'heater for heating engines, and the like, which comprises in combination, Ia casing forming :a combustion chamberwith an inlet opening and an outlet opening located at two opposite extremities thereof,pipe means connected to theoutlet opening of said combustion Chain ber and communicating therewith, said pipe means and said combustion chamber being arranged in substantially axial alignment with each other, an open-ended tubular means having one end disposed in opposed alignedre'la- 'ti-on to said combustion chamber inlet opening, fuel gas inlet means aligned with the opposite end of'the "tubular means to project fuel therein, manually operable means associated with said tubular means for varying the distance of said one 'end thereof relative to said inlet opening, closed fuel containing means adjacent said combust ion chamber in heat receiving relation thereto, conduit means 'elfecting communication between said "fuel 'con- *taining means and said fuel inlet means, said *fuel inlet means -having associated therewith a fuel flow control element, manually operable means associated with said control element 'for varying the supply of fuel through said 'fuel inlet means, and means operable automatically in response to thefuel ,gaspressurefor varying the;position .of said fuel control element to increase the ,fuel supply through said inlet means in ,consequence of predetermined increases in the fuelgaspressure;

In combination in .a heater for heating .up engines, cooling systems andsimilarstructures, a-casingforming a combustion chamber provided with an inlet openingand an outlet opening arranged :at .two opposite extremities thereof, ,pipe :means connected at said outlet opening ,and communicating with said combustion chamber, an openended tubular control ,means having one zendwaligned with said inlet opening invariably spaced relation :thereto to communicate therewith, fuel admission means aligned :Wlth the. opposite end :of said tubular control means as communicate therewith, valvemeans associated with said "fuel admission means and movable to vary the snpply of fuel to said tubular means, manually operable means assoc'iated with said tubular control means for varying the position thereof-relative to said fuel admission means and to said inlet opening, said fuel admission means also including fuel inlet means and chamber means communicating with said fuel inlet means, gas pressure responsive means having'one end stationarily mounted and having its other end connected to said valve means to thereby move said valve means toward valve opening position in response to an increase in pressure in said chamber means, and to move said valve means towardvalve closing position in response to a decrease in pressure in said chamber means, and means operatively connected with said valve means for arresting the latter in two different positions corresponding to two different pressures in said chamber means.

3. In a fuel control assembly for use in connection with heaters adapted to work according to the resonance principle, a casing having an inlet for fuel and fuel gas and also comprising a chamber communicating with said inlet, a nozzle provided with an outlet opening, a valve member cooperating with said outlet opening and movably arranged so as to vary the flow-of fuel and fuel gas from said inlet through said outlet opening, pressure responsive means associated with said valve member and operable in response to an increase in pres sure in said chamber to move said valve member toward valve opening position, and operable in response to a decrease in pressure in said chamber to move said valve member toward valve closing position, lever means connected to said valve member and movable thereby, first yielding means continuously urging said lever means and said valve member toward valve closing position, said first yielding means being operable to yield in response to a predetermined pressure in said chamber, thereby permitting said first yielding means and said valve member to move. toward valve opening position, abutment means associated with said yielding means for arresting the adjacent lever portion in response to a predetermined stroke of said yielding means, second yielding means spaced from said first yielding means and continuously urging said lever means and said valve member toward valve closing position, said second yielding means being adapted to yield in response to a predetermined pressure in said chambergreater than said first mentioned predetermined pressure, and additional abutment means associated with said last mentioned yielding means for arresting the adjacent lever portion in response to a predetermined stroke thereof greater than said first mentioned predetermined stroke.

4. In a fuel control assembly for use in connection with heaters adapted to work according to the resonance principle, a casing having an inlet for fuel and fuel gas and also comprising a chamber communicating with said inlet, a nozzle provided with an outlet opening, a valve member cooperating with said outlet opening and movably arranged so as to vary the flow of fuel and fuel gas from said inlet through said outlet opening, pressure responsivemeans associated with said valve member and operable in response to an increase in pressure in said chamber to move said valve member toward valve opening position, and operable in response to a decrease in pressure in said chamber to move said valve member toward valve closing position, lever means connected to said valve member and movable thereby, first yielding means continuously urging said lever means and said valve member toward valve closing position, said first yielding means being operable to yield in response to a predetermined pressure in said chamber, thereby permitting said first yielding means and said valve member to move toward valve opening position, abutment means associated with said first yielding means for arresting the adjacent lever portion in response to a predetermined stroke of said first yielding means, second yielding means spaced from said first yielding means and continuously urging said lever means and said valve member toward valve closing position, said second yielding means being adapted to yield in response to a predetermined pressure in'said chamber greater than said first first mentioned predetermined pressure, additional abutment means associated with said second yielding means for arresting the adjacent lever portion in response to a predetermined stroke thereof greater than said first mentioned predetermined stroke, and adjustable means for varying said first mentioned and said second mentioned abutment means to thereby vary the respective strokes in response to said first mentioned and said second mentioned pressures in said chamber.

5. in a fuel control assembly for use in connection with heaters adapted to work according to the resonance principle, a casing having an inlet for fuel and fuel gas and also comprising a chamber communicating with said inlet, a nozzle provided with an outlet opening, a valve member cooperating with said outlet opening and movably arranged so as to vary the flow of fuel and fuel gas from said inlet through said outlet opening,

pressure responsive means associated with said valve member and operable in response to an increase in pressure in said chamber to move said valve member toward valve opening position, and operable in response to a decrease in pressure in said chamber to move said valve member toward valve closing position, lever means connected to said valve member and movable thereby, first yielding means continuously urging said lever means and said valve member toward valve closing position, said first yielding means being operable to yield in response to a predetermined pressure in said chamber, thereby permitting said first yielding means and said valve member to move toward valve opening position, abutment means associated with said firstyielding means for arresting the adjacent lever portion in response to a predetermined stroke of said yielding means, second yielding means spaced from said first yielding means and continuously urging said lever means and said valve member toward valve closing position, said second yielding means being adapted to yield in response to a predetermined pressure in said chamber greater than said first mentioned predetermined pressure, additional abutment means associated with said second yielding means for arresting the adjacent lever portion in response to a predetermined stroke thereof greater than said first mentioned predetermined stroke, and manually operable means operatively connected with said valve member for actuating the same to positively close said outlet opening.

6. A heater for heating engines and similar structures, which comprises in combination, a casing forming a main combustion chamber having an inlet opening and an outlet opening at two opposite extremities thereof, said combustion chamber having a size between said inlet opening and said outlet opening such that the crosssectional area thereof is substantially greater than that of said inlet opening, pipe means connected to said combustion chamber at said outlet opening, said pipe means and said outlet opening having substantially the same cross sectional areas, a fuel supply control mechanism including a valve member and a fuel discharging element, a tubular control member open at both ends and having opposite ends aligned with and variably spaced from said inlet opening and said fuel discharging element,

said tubular control memberbeing adapted to receive fuel from said discharging element to act as an auxiliary combustion chamber and to convey combustion gases to said main combustion chamber, manually operable means operatively connected with said tubular control member to move the latter relative to said inlet opening and said fuel discharging element for selectively transferring the main center of combustion from said tubular control member to said main combustion chamber and for varying the admixture of air to the fuel delivered by said fuel supply control mechanism, control means associated with said valve member for arresting the same at a first partially open position and a second more l d n I fully opened 'POSIHQII corresponding respectlvely to .relajtively ,low and to relatively high temperature pressure .conditions of the heater, and manually operable means .operable to vary said valve member independently of said control means.

' 7.. Aheater for heating engines and similar structures, which comprises in combination, a casing forming a main combustion chamber :in tubular form having an .inlet opening and an outlet opening 'at two opposite extremities thereof, said:conibustion chamber having a size between said inlet opening and said outlet opening such that the cross-sectional area thereof .is substantially greater than that of said inlet openingpipe means connectedto saidcombustion chamber at ,said outlet opening, ,said pipe means and .said outlet opening "having substantially the same diameters, va fuel .supply control ,mechanism including a valve member and a fuel dis charge element, a tubular control member open at both ends and interposed between said inlet .opening andsaid fuel discharge element, one end of said tubular memher being aligned with and variablyspaced from said fuel discharge element for receiving a fuel-air .mixture therefrom, the other end of said tubular control member being aligned with and variably spaced 'from said inlet opening whereby said tubular control member is adapted ,to act 'asan auxiliary combustion chamber and .to convey combustion gases to said main combustion chamber, manually operable means operatively connected with said tubular control member for moving the latter relative to said inlet opening ,and said fuel discharge element for selectively transferring the main center of combustion "from said auxiliary combustion chamber formed "by ;said tubular member to said main combustion chamber and for "varying the admixture of a'irto the fuel delivered 'bysaid'fuel'supply control mechanism, control means associated with said 'valve gmembet for arresting the same at a first intermediate position :and a second more fully opened position ;corresponding respectively-to relatively low and to relatively hightemperature pressure conditions of the heater, manually operable means operableto vary said valve member independent of said "control means, and supporting means associated with said"heater for selectively holding the same in substantially inclined position.

8. Aiheaterfor heating engines, cooling systems therefor and similar structures, which comprises in combination, a casing forming a *main combustion chamber in ttubularrform having .an inlet opening and an outlet topenn'ngat two ,opposite extremities thereof said combustion phamberfhaving a size between said inlet opening and {said outlet opening such that the cross-sectional area tthereof is substantially greater than that of said tirzlet opening, pipe means connected to said-.combustion-chamtbQIfflI-agfiid-Olltlftt opening, said pipe means and said outlet opening having substantially the same diameters 'a:fue1 ssupplytcontrol mechanism including ,a valve member and attfuel-zdischarge element, a tubular control membertopen eat both ends and interposed between said inlet opening rand said fuel discharge element, onetend of said tubular tmember-beingaligned with but var-,iablytspaced fromsaid partially open position and a second more fully open ,position corresponding .respective'ly to relatively ,low and to relatively high temperature pressure conditions of the .heater, manually operable means operable to vary said valve member independent of said control means, and means associated with sa'id parallelogram lever means for selectively arresting the .same in a plurality of desired positions. t p

9. Aheater'forheatingup engines and the like, conipris'ing, in combination, a casing 'forming a tubular combustion chamber having an inlet opening and an outlet opening, said combustion chamber having a size between said inlet opening and said outlet opening such that the cross-sectional area thereof is substantially greater than the larger of sa'id'inlet and outlet openings, pipe means connected to said combustion chamber and communi- .cating with said outlet opening, Said pipe means and said tfuel discharge element for receiving a fuel-air mixture ttliereftrom, the other end of said -.-.tubular'- control :member being aligned with but variably spaced from said inlet opening whereby said tubular member is adapted to act as an auxiliary combustion chamber and to convey combustion gases to said main combustion chamber, parallelogram lever means operatively connected with said tubular control member for moving the latter relative to said inlet opening and said fuel discharge element for selectively transferring the main center of combustion from said auxiliary combustion chamber formed by the tubular member to said main combustion chamber and for varying the admixture of air to the fuel delivered by said fuel supply control mechanism, control means associated with said valve member for arresting the same at a first outlet opening having substantially the same diameter, "tubular means open at both ends ;and having one end aligned with .andfldirectly opposite said inlet opening to communicate therewitl' 'fuel gas inlet meansaligned with ;the opposite end of said tubular means, operating means connected with said tubular means to move the latter toward and away from said combustion chamber inlet opening .to createvariable spacings between opposite ends .of the tubular means and the combustion chamber inlet opening and the fuel inlet means along the axis of the tubular means said combustion chamber and pipe means .being shaped and dimensioned to define with said tubular member a space "acoustically resonant in a frequency :range suitable to sustain combustion by cyclic detonations, :and said tu'bu'lar means being "shaped and dimensioned in relation to the combustion chamber and said pipe .means to effect a substantial change in the natural frequency of the acoustically resonant space including the combustion chamber as .an incident to movement of the tubular means toward and away from the combusti'on "chamber inlet.

"10. A {heater for producing heating gases for heating engines and the like, comprising, in combination, a casingforming a tubular combustion chamber with an in- .let opening and an outlet opening, pipe means connected to said combustion chamber and communicating with said "outlet openi g, tubular means open at both ends and .having 'one' end aligned .with and "directly opposite said combustion chaniberinlet opening-said combustion chamber and said pipe means being shaped and dimensioned to define "with said "tubular means a space acoustically resonant within 'a-frequency range suitable to sustain combust'ion by cyclic detonations,fuel gas inlet means aligned with "the other end of said tubular means, means mount- ;ing said tubular means for axial movement, said tubular means having a length 'considerably'shorter than the dis ,tance between said combustion chamber inlet opening andsaid fuel 'inlet means to provide'variable spacingalong the axis of the tubular means Ebetween opposite ends thereof and said inlet opening and said fuel inlet'means respectively, and operating means connected with said tubular means for moving the latter along the axis thereof toward and away from -said inlet opening.

ll. The method of operating a detonating 'a'ir heater having means defininga combustion space open at :opposite'ends and acoustically resonant approximately within a range suitable for sustaining combustion by successive detonations, a tubular preheating and fuel supply member open at both ends, and fuel inlet means, comprising shifting the preheating and fuel supply member away from the combustion space inlet to create a spacing between the inlet and the adjacent end of the preheating member and at the same time maintain an opposing alignment therebetween, supplying fuel from the inlet means to the preheating member,burning fuel in the preheating member to produce hot combustion gases for heating the combustion space to a temperature suitable for sustaining combustion by cyclic detonations, and mov- 1 11 ing the preheating member toward the combustion space to effectively reduce the spacingbetween the combustion space inlet and the adjacent end of the preheating member, while maintaining the fuel supply from the inlet means to the tubular member, thereby causing the center of combustion to shift fromthe preheating member into the combustion space and modifying the effective natural frequency of the acoustically resonant space including the combustion space to assure that combustion by cyclic detonation continues.

12. A cyclically operating detonating heater for supplying hot gases for engine warming purposes or the like, comprising, in combination; means defining a combustion space, an inlet to said space, and an outlet from said space; a tubular preheating member open at both ends and having one end aligned with said combustion space inlet, fuel supply means mounted to supply fuel at all times to the other end of said tubular member, operating means connected with said tubular preheating member to move the latter between a retracted position, in which it operates as an independent burner with the end thereof adjacent said combustion space inlet spaced from said inlet but in alignment therewith to project hot combustion gases into said space, and a second position in which the end of the tubular member adjacent said inlet is carried into closer proximity thereto to direct into said inlet fuel flowing through the tubular member from said fluid supply means; said combustion space and said tubular member being shaped and dimensioned to define, when said tubular member is. moved into proximity with said inlet, an acoustically resonant space having a natural acoustical frequency within a range capable of sustaining cyclic combustion by repeated detonations; and said tubular preheating member being shaped and dimensioned in relation to said combustion space to substantially change the natural frequency of the acoustically resonant space including the combustion space upon movement of the preheating member toward and away from said combustion space inlet.

13. In a detonating air heater, the combination of means defining a combustion space open at opposite ends, a generally tubular preheating and fuel supply member open at both ends and mounted with one end in opposed.

alignment with the combustion space inlet, operating means connected with said member to move the latter between a retracted position in which the end thereof adjacent the combustion space inlet is spaced a substantial distance from the inlet and an advanced position in which the spacing between said inlet and the adjacent end of the member is closed to a large degree; said combustion space and said member being shaped and dimensioned to define, when said member is in advanced position, an acoustically resonant space having a natural frequency within a range suitable for sustaining combustion by cyclic detonations; said preheating and fuel supply member being shaped and dimensioned to effect a substantial change in the natural frequency of the acoustically resonant space including said combustion space upon movement of the member between retracted and advanced positions, a closed fuel container mounted adjacent said combustion space in heat receiving relation thereto, a control valve, passageway means connecting said control valve with said fuel container, means associating said valve with said preheating and fuel supply member to direct fuel from the valve into the end of the member opposite from the combustion space inlet, said valve including a movable flow control element, and pressure responsive actuating means communicating with said fuel container and connected to said movable flow control element to vary the position of the latter to increase the fuel supply to said preheating and fuel supply member through said valve in response to predetermined increases in the fuel pressure within said container.

14. A detonating air heater comprising, in combination, means defining a combustion chamber space and an inlet to and an outlet from said space, a hollow preheating burner member having an inlet therein for admitting fuel and having an outlet therefrom, means mounted to supply a continuous fuel mixture into said burner memher through said inlet thereof, shifting means connected with said burner member to move the latter between a preheating position relatively remote from the combustion chamber space inlet, in which the burner member operates independently of the combustion chamber space and said burner member outlet is positioned to play hot combustion gases into said combustion chamber space through said inlet thereof, and a second position in which said burner memberoutlet is disposed in close proximity to and in alignment with said combustion chamber space inlet to convey a fuel mixture from the fuel supply means through said burner member into said combustion chamber space; said combustion chamber space and said preheating burner member being shaped and dimensioned to define upon movement of the preheating member into proximity into said combustion chamber space inlet a larger space, including said combustion chamber space and the interior of said burner member, acoustically resonant at a frequency in a range suitable for sustaining cyclic detonating combustion; and said preheating burner member being shaped and dimensioned in relation to the combustion chamber space to change substantially upon movement of the preheating member toward and away from said combustion chamber space inlet the natural acoustical frequency of the acoustically resonant space of which said combustion chamber space is a part.

References Cited in the file of this patent UNITED STATES PATENTS 872,810 Friedmann et al Dec. 3, 1907 1,024,209 Lemp Apr. 23, 1912 1,402,747 Doble Jan. 10, 1922 1,617,399 Kress Feb, 15, 1927 1,888,866 Russel Nov. 22, 1932 1,993,748 Noack Mar. 12, 1935 2,071,143 Scott Feb. 16, 1937 2,117,270 Bloom May 17, 1938 2,121,271 Szabo June 21, 1938 2,268,591 Holm Jan. 6, 1942 2,295,177 King Sept. 8, 1942 2,363,168 Findley Nov. 21, 1944 2,464,165 Williams Mar. 8, 1949 2,612,748 Tenney et al. Oct. 7, 1952 2,683,961 Britton et a1 July 20, 1954 

